1. Field of the Invention
The present invention relates to web-based application servers configured for generating web pages for voice enabled web applications within a hypertext markup language (HTML) and hypertext transport protocol (HTTP) framework.
2. Description of the Related Art
The evolution of the public switched telephone network has resulted in a variety of voice applications and services that can be provided to individual subscribers and business subscribers. Such services include voice messaging systems that enable landline or wireless subscribers to record, playback, and forward voice mail messages. However, the ability to provide enhanced services to subscribers of the public switched telephone network is directly affected by the limitations of the public switched telephone network. In particular, the public switched telephone network operates according to a protocol that is specifically designed for the transport of voice signals; hence any modifications necessary to provide enhanced services can only be done by switch vendors that have sufficient know-how of the existing public switched telephone network infrastructure.
FIG. 1 is a diagram illustrating the existing public switched telephone network. As shown in FIG. 1, the public switched telephone network 10 includes a wireline subnetwork 12, a wireless subnetwork 14, and a time division multiplexed (TDM) backbone subnetwork 16 configured for transporting voice data and other data between user devices 18 according to the existing public switched telephone network protocols. The subnetwork 16, for example, includes interexchange trunks for transporting voice data between interexchange carriers and/or local exchange carriers.
As shown in FIG. 1, the wireline subnetwork 12 includes telephony application servers 20 configured for providing voice applications 22 such as subscriber profile management, voice mail, call forwarding, etc. for the user devices 18a, 18b, and 18c coupled to the wireline subnetwork 12. As recognized in the art, the telephony application servers 20 include advanced intelligent network (AIN) components such as services control point (SCP) directories and service nodes (SN) configured for controlling the telephony applications 22. The wireline subnetwork 12 also includes telephony access services 24 configured for providing the user devices 18a, 18b, and 18c access to the wireline subnetwork using, for example, analog twisted pair connections or ISDN connections to a central office. The user devices 18a, 18b, and 18c, illustrated as a cordless telephone 18a, a fax machine 18b having a connected telephone, and an analog telephone 18c, are referred to herein as xe2x80x9cskinny clientsxe2x80x9d, defined as devices that are able to interface with a user to provide voice and/or data services (e.g., via a modem) but cannot perform any control of the application 22 or the protocol used to interface with the wireline subnetwork 12.
The wireless subnetwork includes wireless application servers 26, and wireless access services 28 for providing wireless voice and data services to the wireless user devices 18d, 18e, and 18f. The wireless user devices 18d, 18e, and 18f, illustrated as a cellular telephone (e.g., AMPS, TDMA, or CDMA) 18d, a handheld computing device (e.g., a 3-Com Palm Computing or Windows CE-based handheld device) 18e, and a pager 18f, interact with the wireless application 30 based on respective wireless protocols controlled by the wireless access services 28. The wireless application servers 26 control wireless services such as home location register (HLR) management, and service node (SN) telephony applications. xe2x80x9cTiny clientsxe2x80x9d are distinguishable from skinny clients in that the tiny clients tend to have even less functionality in providing input and output interaction with a user, and may not be able to send or receive audio signals such as voice signals at all. Examples of tiny clients include wireless user devices 18d, 18e, and 18f, as well as function-specific terminal devices. Note that tiny clients tend to be one-way (receive-only or transmit-only) devices.
In both cases, however, both skinny clients and tiny clients have no control of the respective applications 22 and 30 that are running within the respective networks. Rather, the applications 22 and 30 are executed exclusively by the servers 20 and 26. Moreover, both skinny clients and tiny clients have no control of the access protocol used to access the respective subnetworks 12 and 14; hence, the skinny clients and tiny clients are currently incapable of initiating access to another network using an alternative protocol, for example Internet protocol (IP). Consequently, the skinny clients and tiny clients rely exclusively on the service nodes of the servers 20 and 26 to provide the voice application services programmed in the applications 22 and 30, respectively. Although this exclusive control of the applications 22 and 30 by the servers 20 and 26 is advantageous in maintaining control over quality of service and reliability requirements, the applications 22 and 30 can only be developed and maintained by programmers having sufficient know-how of the public switched telephone network infrastructure. As a result, programmers familiar only with open standards such as IP are unable to provide contributions in enhancing the applications 22 and 30 due to the limitations of the public switched telephone network paradigm.
FIG. 2 is a diagram illustrating the web client-server paradigm of an open standards-based IP network 40, such as the World Wide Web, the Internet, or a corporate intranet. The IP network 40 provides client-server type application services for clients 42a and 42b by enabling the clients to request application services from remote servers using standardized protocols, for example hypertext transport protocol (HTTP). The web server application environment 46 includes web server software, such as Apache-based software available from The Apache Software Foundation, implemented on a computer system attached to the IP network 40. Applications 48 are composed of HTML pages, logic, and database functions. In addition, the web server 46 may provide logging and monitoring capabilities.
When the application 48 is written by an application designer, pages are created using an editor. Logic and functions are written in a programming language, such as C, C++, Java, etc. These applications are compiled or interpreted and are invoked through a web server facility such as a Common Gateway Interface (CGI). Hence, pages may be created dynamically by the application 48 as it is executing.
The client 42a, for example, is a stand-alone personal computer or workstation that has its own application 44 for providing its own application services. The client 42a can access the remote web application server 46 that executes the application services 48 via an IP-based packet switched network 50 using either remote access services 52 or local area network access services 54, if available. Similarly, the client 42b having only a browser 56 can also enjoy the services of the applications 44 and 48 by accessing the respective computers 42a and 46.
The clients 42a and 42b, referred to herein as xe2x80x9cfat clientsxe2x80x9d and xe2x80x9cthin clientsxe2x80x9d, respectively, have the distinct advantage that they can initiate requests using IP protocol to any connected web server 46 to execute part or most of the applications 48 on behalf of the clients. An example of a fat client 42a is an e-mail application on a PC that knows how to run the application 44 and knows how to run the IP protocols to communicate directly with the messaging server via the packet switched network 50. An example of a thin client 42b is a PC that has a web browser; in this case, the web browser 56 can use IP protocols such as HTTP to receive and display web pages generated according to hypertext markup language (HTML) from server locations based on uniform resource locators (URLs) input by the user of the PC.
Hence, the web server paradigm enables the clients to access any web server on the IP network 40. Moreover, the use of open protocols such as HTTP and HTML enable any client, regardless of its configuration, to access an HTML web page from a server that has no knowledge of the configuration of the requesting client; if the HTML web page received by the client includes information such as a specific HTML tag that is not recognizable by the browser 56, the browser 56 can merely ignore the unrecognized HTML tag.
Efforts have been made to integrate the telephony applications 22 and 30 directly onto the IP network 40 by developing protocol translators that provide a termination between the telephony applications servers 20 and 26 and the web application servers 46. One such proposal is referred to as voice over IP, where telephony data from the telephony applications 22 and 30 are repackaged into IP packets for transmission across the IP network 50. These efforts, however, still require programmers who have substantial know-how of the telephony applications 22 and 30 and the public switched telephone network infrastructure. Moreover, the repackaging of telephony data into IP packets creates substantial problems in transmission of the telephony data, since the transport of IP data packets is not sequential and synchronous, as required for the voice applications.
Another attempt at performing voice applications over an IP network involves rewriting the telephony applications 22 and 30 as scripts in extensible markup language (XML), and sending the XML scripts over the IP network to an interpreter that is coupled to a telephone. The interpreter then plays the received XML scripts for the telephone. However this approach merely transfers some application functionality from the telephony applications 22 and 30 to the interpreter, and still requires telephony application engineers to write XML scripts of the applications 22 and 30. Hence, the IP network is used only for transporting the XML scripts, and does not take advantage of the open standards-based flexibility of the IP network that has provided enormous growth in web infrastructure and Internet commerce.
As described above, the efforts to date at extending the voice applications 22 and 30 from the public switched telephone network to the IP network 40 have had limited success, primarily because the telephone protocols used in development of the applications 22 and 30 do not operate under the same paradigm as the IP network 40. For example, the telephony applications 22 and 30 are state aware, ensuring that prescribed operations between the application servers 20 or 26 and the user devices 18 occur in a prescribed sequence. For example, operations such as call processing operations, voicemail operations, call forwarding, etc., require that specific actions occur in a specific sequence to enable the multiple components of the public switched telephone network to complete the prescribed operations.
The applications 44 and 48 running in the IP network 40, however, are state-less and transient in nature, and do not maintain application state. These applications 44 and 48 are state-less because application state requires an interactive communication between the browser and back-end database servers accessed by the applications 44 and 48. However, an HTTP server provides asynchronous execution of HTML applications: the applications 44 and 48, in response to reception of a specific request in the form of a URL from a client 42, instantiate a program configured for execution of the specific request, send an HTML web page back to the client 42, and terminate the program instance that executed the specific request. Hence, all active information about the HTML page or application processed is cleared, with the exceptions of log data.
Although application state information could be passed between the browser 56 and a web application 48 using a data file referred to as a xe2x80x9ccookiexe2x80x9d, some users prefer not to enable cookies on their browser 56; in addition, the passing of a large amount of state information as would normally be required for voice-type applications between the browser 56 and the web application 48 would substantially reduce the bandwidth available for the client 42, rendering use of the cookie infeasible for voice enabled web applications. Moreover, the use of a cookie is especially infeasible if user specific attributes also needed to be passed between the web application server 46 and the browser 56.
Hence, the above-described problems associated with the IP network 40 result in substantial difficulties in attempting to write and manage web voice applications. The nature of voice applications, due to the limitations of input/output capabilities, results in the application 48 needing to do more processing to maintain the user interface as simple as possible. Moreover, the necessity of a standard development environment to write the application in a programming language such as C, C++, PERL, Java, etc., limits the flexibility of the application developer in developing an efficient application suitable for voice applications. Finally, web applications are visual by their nature and lack robust audio content and control, and web servers and their corresponding programming environment do not have a means to simplify the audio content and control.
There is a need for an arrangement that enables voice applications to be easily implemented on an IP packet switched network using the open standards-based flexibility of the IP network.
There is also a need for an arrangement that enables voice applications to be implemented using HTTP and HTML open standards, enabling development of voice applications by individuals that do not have expertise in the public switched telephone network. For example, there is a need for an arrangement that enables voice applications to be designed by web programmers.
There is also a need for an arrangement that enables voice applications to be implemented using an IP network, without the necessity of the public switched telephone network.
There is also a need for an arrangement that enables unified voice messaging services to be provided via an IP network to a web browser, where voice enabled web applications can be written and implemented without the necessity of a programming language development environment.
These and other needs are attained by the present invention, where an application server executes a voice-enabled web application by runtime execution of extensible markup language (XML) documents that define the voice-enabled web application to be executed. The application server includes a runtime environment that establishes an efficient, high-speed connection to a web server. The application server, in response to receiving a user request from a user, accesses a selected XML page that defines at least a part of the voice application to be executed for the user. The XML page may describe any one of a user interface such as dynamic generation of a menu of options or a prompt for a password, an application logic operation, or a function capability such as generating a function call to an external resource. The application server then parses the XML page, and executes the operation described by the XML page, for example dynamically generating an HTML page having voice application control content, or fetching another XML page to continue application processing. In addition, the application server may access an XML page that stores application state information, enabling the application server to be state-aware relative to the user interaction. Hence, the XML page, which can be written using a conventional editor or word processor, defines the application to be executed by the application server within the runtime environment, enabling voice enabled web applications to be generated and executed without the necessity of programming language environments.
According to one aspect of the present invention, a method is provided in a server configured for executing web applications. The method includes receiving a first hypertext markup language (HTML) request, generated by a user browser, for a first page for transport to the user browser via a Hypertext Transport Protocol (HTTP) connection. The method also includes accessing a selected extensible markup language (XML) page in response to reception of the first HTML request, and generating the first page based on runtime execution of the selected XML page by the server, the generating step including supplying voice application control content within the first page for execution by the user browser. Generation of the first page based on runtime time execution of the selected XML page enables voice application control to be supplied by the application server to a web browser, merely by implementing XML pages that define the application to be executed. Hence, web based voice applications can now be developed using open-source XML document development tools such as forms-based document development systems, as opposed to development environments that require compiling applications written in programming languages such as C, C++, PERL, Java, etc. Hence, voice enabled web can now be developed by individuals without the necessity of programming language experience.
Another aspect of the present invention provides a server system configured for executing voice web applications. The system includes an extensible markup language (XML) database configured for storing a plurality of XML documents, each XML document specifying at least one executable voice web application parameter. The system also includes an executable resource configured for runtime execution of the XML documents, the executable resource including an XML parser configured for parsing at least a first of the XML documents selected based on a received hypertext markup language (HTML) request from the user browser across a hypertext transport protocol (HTTP) connection. The executable resource dynamically generates an HTML response to the HTML request that includes voice application content, based on the corresponding executable voice web application parameter parsed from the first XML document. Storage of XML documents within the XML database enables individuals to generate voice enabled web applications using documents, merely by preparing XML documents that describe the voice enabled web application, and storing the XML documents in the XML database. Hence, the executable resource is able to parse the selected XML document to execute the necessary application operation in a runtime environment for the HTML request. Hence, the server system can efficiently execute voice enabled web applications in a manner that is more efficient than existing server systems that rely on applications developed from compiled programming languages.
Additional advantages and novel features of the invention will be set forth in part in the description which follows and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The advantages of the present invention may be realized and attained by means of instrumentalities and combinations particularly pointed out in the appended claims.